From patchwork Tue Oct 21 10:48:58 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dheeraj Jamwal X-Patchwork-Id: 5116461 Return-Path: X-Original-To: patchwork-ltsi-dev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 349D5C11AC for ; Tue, 21 Oct 2014 11:26:46 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2BB4D200D4 for ; Tue, 21 Oct 2014 11:26:45 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3C362200CA for ; Tue, 21 Oct 2014 11:26:44 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 116ADE20; Tue, 21 Oct 2014 11:03:58 +0000 (UTC) X-Original-To: ltsi-dev@lists.linuxfoundation.org Delivered-To: ltsi-dev@mail.linuxfoundation.org Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id AEF23C01 for ; Tue, 21 Oct 2014 11:03:56 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 5275C1FAB2 for ; Tue, 21 Oct 2014 11:03:56 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 21 Oct 2014 04:03:56 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,761,1406617200"; d="scan'208";a="617795063" Received: from ubuntu-desktop.png.intel.com ([10.221.122.25]) by fmsmga002.fm.intel.com with ESMTP; 21 Oct 2014 04:03:55 -0700 From: Dheeraj Jamwal To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 21 Oct 2014 18:48:58 +0800 Message-Id: <1413889294-31328-339-git-send-email-dheerajx.s.jamwal@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> References: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> MIME-Version: 1.0 X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org Subject: [LTSI-dev] [PATCH 0338/1094] drm/i915: Avoid div by zero when pixel clock is large X-BeenThere: ltsi-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: "A list to discuss patches, development, and other things related to the LTSI project" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org X-Virus-Scanned: ClamAV using ClamSMTP From: Ville Syrjälä Make sure the line_time_us isn't zero in the gmch watermarks code as that would cause a div by zero. This can be triggered by specifying a very fast pixel clock for the mode. At some point we should probably just switch over to using the same math we use on PCH platforms which avoids such intermediate rounded results. Also we should verify the user provided mode much more rigorously. At the moment we accept pretty much anything. Note that "very fast mode" here means above 74.25 GHz. Signed-off-by: Ville Syrjälä Reviewed-by: Chris Wilson [danvet: Add Ville's clarification of what "very fast" means.] Signed-off-by: Daniel Vetter (cherry picked from commit 922044c9dfec40d5adc5d4a757f802e55e3d0a85) Signed-off-by: Dheeraj Jamwal --- drivers/gpu/drm/i915/intel_pm.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 7b4e676..ad58ce3 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -1134,7 +1134,7 @@ static bool g4x_compute_wm0(struct drm_device *dev, *plane_wm = display->max_wm; /* Use the large buffer method to calculate cursor watermark */ - line_time_us = ((htotal * 1000) / clock); + line_time_us = max(htotal * 1000 / clock, 1); line_count = (cursor_latency_ns / line_time_us + 1000) / 1000; entries = line_count * 64 * pixel_size; tlb_miss = cursor->fifo_size*cursor->cacheline_size - hdisplay * 8; @@ -1210,7 +1210,7 @@ static bool g4x_compute_srwm(struct drm_device *dev, hdisplay = to_intel_crtc(crtc)->config.pipe_src_w; pixel_size = crtc->fb->bits_per_pixel / 8; - line_time_us = (htotal * 1000) / clock; + line_time_us = max(htotal * 1000 / clock, 1); line_count = (latency_ns / line_time_us + 1000) / 1000; line_size = hdisplay * pixel_size; @@ -1443,7 +1443,7 @@ static void i965_update_wm(struct drm_crtc *unused_crtc) unsigned long line_time_us; int entries; - line_time_us = ((htotal * 1000) / clock); + line_time_us = max(htotal * 1000 / clock, 1); /* Use ns/us then divide to preserve precision */ entries = (((sr_latency_ns / line_time_us) + 1000) / 1000) * @@ -1569,7 +1569,7 @@ static void i9xx_update_wm(struct drm_crtc *unused_crtc) unsigned long line_time_us; int entries; - line_time_us = (htotal * 1000) / clock; + line_time_us = max(htotal * 1000 / clock, 1); /* Use ns/us then divide to preserve precision */ entries = (((sr_latency_ns / line_time_us) + 1000) / 1000) *